Process for improving coppertitanium alloys



Besides, other copper alloys are known which aging for 24 hours at a temperature of 350 C. 10

' said alloys, the aging being caused by the soluelongation is obtained by cold-stretching after 15 45 I Q10! three w is per cent had a resistance of 0.089

"Patented Feb. 12, 1935 V v 1,991,162

UNITED STATES PATENT OFFICE to Metal & Thermit' Corporation, Cartel-ct, N. -J., a corporation New Jersey No Application January 23, 1930, ?;;i9alNo.422,955. InGermanyFebrnary28,

'2 Claims. (01. us-21.2)

It is generally known that by means of an addi of 31.2 per cent, a reduction of area of 74.9 per tion of beryllium to copper, alloys can be procent. I duced subject to be'hardened, after being sub An alloy containing 3.05 per cent of titanium iected to a special improving process, the sosubjected to the same treatment, gave the fol- -5 called aging. These alloys are quenched at lowing results: 5 high temperatures, preferably between 700 and Quenched at a temperature of 850 C. a tensile 1000 C., and considerable hardness is obtained strength of 42.6 kg/mm, an elongation of 32.5 by annealing at a lower temperature, between per cent, a reduction of area of 79.8 per cent, a 250 and 450 C. the so-called aging. hardness of 80.4. After quenching from 850 and can be highly strengthened by means of a similar it possessed a tensile strength of 73.4 kg/mm an aging process. Mention can be made of the elongation of 30.0 per cent, a reduction of area of ternary copper+silicon alloys with additions of ,60.5%, and a hardness of 1'75.

chromium, nickel, cobalt, iron, or manganese, in An extremel high strength with suiflcient bility of the silicides. Further mention can be aging. The alloy with 2.15 percent of titanium made of the copper alloys containing aluminum after aging and cold-stretching to 43 per cent and a metal of the iron group, such as manganese, showed the following figures: I a as well as the ternary copper alloys with-mag Tensile strength 100,7 kg/mm, elongation 6.5 nesiumand tin. per, cent,-reduction of area 38.3 per cent. 20 I have found that titanium which up to now The alloy with 3.05 per cent of titanium after is scarcely used in alloying practice, and for this the same cold-stretching gave the following reason is of comparatively low value, is able to resultsqgive valuable properties to copper alloys, .inas- Tensile strength 113.4kg/1nm elongation 6 much as these alloys like the above-named, can per cent, reduction of area 38.2 per cent. 25 4 be improved by means of subsequent aging after It is obvious that at a cold-stretching of 43 being quenched from a higher range of temperper cent the workability has not reached its ature. maximum. If the elongation of an alloy with The eflect of titanium on copper has been the 3 per cent of titanium is lowered to 1 per cent, subject of much research work which, however, a tensile strength of 130 to 140 lag/mm can be 30 till now was restricted to examining very impure reached. An alloy with 4 per cent of titanium alloys of copper and titanium, and wholly inexact attains after aging and cold-stretching a tensile values concerning the mechanical properties and strength of 150 kg/mm and an elongation of the electrical resistance, were determined. More- 1 per cent. over, in the tests made till now-the ageability of The effect of aging on the electrical resistance 35 copper-titanium alloys and its great influence on is xtr rdinarily sr Th 1 3" w -05 the electrical conductivity have been wholly, over- D cent titanium contents install! has after looked. 1 quenching a resistance of 0.406 ohm/m/mm=. The mechamcal properties of very pure copmb After aging for 21 hours at 350 C. the resistance 40 1 M Th decreases to 0.142 ohm/m/mm, i. e. to almost 4 4 grzw fgg j fi :figgig g g; s: of one third of its previous value. Regarding the lowest resistance to be produced by aging, alloys stm possessing good mums properties can with smaller titanium contents give morebe increased from 140 to 225W quenching from favourable results Thus an alloy with 2.15 per in water and subsequently aging cent of titanium after aging and cold-stretching Another copper-titanium alloy containing 2.15 Ohm/m/mm v per cent of titanium showed thefollowing me- The extremely high tensile strength of this 7 P W" alloy'in addition allows of an advantageous use Quenchedat temperature 0! tensile of these alloys for telephone wires or conducting 50 strength of 35.9 kg/mm' f, an elongationof 32.5 w The advantage in comparison with m per cent, a reduction of area of 60.9 percent. The alloys gmployed for t purpose, n 1 th 1 1 1 same alloy quenched from 850 and aged for 24 elongation of copper-titanium alloys. The tlnhours at a temperature of 350 0., showed a bronze with 6 per cent of tin, for example, in a tensile strength of 66.8 kg/mm', an elongation the cold-stretched condition only has a tensile 55 for construction purposes,

strength of 100 kg/mm and an elongation of 0.5 per cent, whereas the copper titanium alloy with 2.15 per cent of titanium has a 13 times higher elongation and the same tensile strength. For this reason copper-titanium alloys, eventually after even higher cold-stretching, are especially suitable in such cases where big distances are to be bridged over with conduction wires and the electrical resistance is not of decisive significance. In such cases, the copper-titanium alloys, owing to their greater resistance toatmospheric influences, should be given the preference over steel which, in addition, has a considerably higher electrical resistance.

Ternary copper-titanium alloys may also be used instead of the binary alloys which, are relatively dimcult to manufacture, and in particular alloys containing metals of the iron group or light metals besides titanium may beemployed.

Oi such alloys mention shall be made of:

Alloys with maximum titanium content of 4 per cent and up to 10 per cent of nickel, chromium, manganese, iron, cobalt, and molybdenum;

Alloys with maximum titanium content oi 4 per cent and up to 5 per cent of silicon, mag-' nesium, aluminum.

The properties of these alloys can be derived strength may be increased for 20 lrg/nim at amaximum. These alloys are in general employed for example for pressed rods, tubes, and so on. Owing to the higher resistance alloys with more constituents are less suitable for conducting purposes.

The most favourable quenching temperature for binary copper-titanium alloys is between 750 and 850 C. Alloys with more constituents, in

particular those with metals of the irongroup, require a higher quenching temperature. The limits within which quenching may be eifected, are between 650 C. and the melting point. Alloys quenched at higher temperatures are more soft; they age relatively in a greater degree.

The most preferable aging temperature is about 350 C. with an aging time of 24 hours. If aging takes place at a higher temperature, a shorter time must be chosen. Alloys with several metals, in-particular those with the metals of the iron group require a somewhat higher aging temperature. In general. the aging temperature is between 250 and 600 C.

Similar aging eflects may be obtained with casting alloys, but these require a longer time of heating before quenching.

In many cases, it is sufllcient to heat the alloys for some time at a high temperature, and after simple cooling in air quite a considerable hardness can be obtained in the subsequent aging Quenching, therefore, is by no means I absolutely n. cooling down from a higher range of temperature is suillcient to attain considerable hardness in the aging process.

What I claim is:-'

1. A process. for improving copper-titanium alloys including a predominating amount of copper and some titanium which comprises cooling said alloys from temperatures of about 650 to 1000 C. and then aging them at about 250 to 600 C. Y

2. A process for improving copper alloys including .l to 4 per cent titanium which comprises quenching the said alloys at temperatures of about 650 to 1000" C. and then aging at about 250 to 600 C.

3. The process for treating an alloy consisting substantially of copper and titanium, the titanium being present-in the alloy in but minor quantity, said process comprising heating said alloy to a temperature between about 650. C. to 1000 C., quickly cooling the alloy, and then reheating it to a temperature between about 250 C. to 669 C.

s. The process of treating an alloy consisting substantially of copper and titanium, the titanium being present in but minor quantities; said process comprising heating said alloy to a relatively high temperature, quenching the alloy. and then reheating it to a relatively low temperature to age-harden the alloy.

5. Heat-hardened copper-titanium alloys containing titanium in quantities ranging'from a small but detectable amount up to about 5 per cent by weight, the balance being substantially copper; saidalloys having the tensile strength, electrical resistance and other properties produced by a heat treatment comprising heating said alloy to temperatures ranging from about 650 to 1000" C., followed by aging at temperatures of from about 250 to 600 C. v I

6. Heat-hardened copper-titanium alloys con taining titanium in quantities ranging from a small but detectable amount up to about 4 per cent by weight and alsocontaining up to 10 per cent of additional hardening metals selected from a group consisting of nickel, chromium, manganese, iron, cobalt and molybdenum; said alloys having the tensile strength, electrical resistance and. other properties produced by a heat treatment comprising heating said alloy to temperatures ranging from about 650 to 1000 C., followed by aging at temperatures of from about 250 to 600 c.

7. The procesaof treating an alloy containing titaniumin quantities ranging from a small but detectable amount up to about 4 per cent by weight and also containing up to 10 per cent of additional hardening metalsselected from a group consisting of nickel, chromium, manganese, iron,

cobalt and molybdenum, said process comprising heating said alloy to temperatures ranging from about 650 to 1000 C., followed by aging at temperatures of from about 250? to 600 C. 

